With more and more people taking direct-to-consumer genetic tests, a Toronto-based genetic counselor says she's seen a number of patients with increased anxiety over results that turned out to be false positives, the Toronto Star reports.
"Within the last year or two years, we've been receiving more and more referrals from surgeons or family doctors for patients who have gotten this type of information from third party interpretation services and then don't know what to do with the information," Seema Panchal, a genetic counselor at the Marvelle Koffler Breast Centre, tells it.
She recounts a situation in which a women in her 30s with no family history of breast cancer received a result that indicated she had a BRCA1 mutation and sought out her doctors for screening and surgical options. But as Panchal tells the Star, the result was a false positive.
Such false positives can affect up to 40 percent of DTC test results and about 17 percent of results can be misinterpreted as high risk when they are not, the Star notes, citing an analysis by Ambry Genetics of raw results. Panchal and another genetic counselor further tell it these results can be due to a range of factors including how the variants are analyzed and if they are viewed within the context of family history.